The mileage you earn for each flight depends on the distance between the origin and destination as calculated by the International Air Transport Association (IATA) and the mileage earnings ratio for the booking class that you travelled in. Please note that IATA distance figures are subject to change.Mileage is calculated in kilometres.In the event of a voluntary or involuntary carrier change, mileage will be calculated according to the operating carrier's mileage policy. Mileage accrual terms and conditions http://ffp.airchina.com.cn/phxplan/#/tabmian?categoryId=305

Qualifying mileage:Mileage earned through flying that is used to count toward your membership upgrade and renewal. Eligible flights are those operated by an Air China Group carrier under a Star Alliance member airline code or Air China Group carrier code, or any Star Alliance member carrier’s operating flights codeshared with any other airline. Flights with Star Alliance Connecting Partners are excluded.

Qualifying segments:Segments accumulated while flying that are used to count toward your membership upgrade and renewal. Eligible segments are those operated by Air China Group carriers under a Star Alliance member airline code or Air China Group carrier code, or some bookings operated by a Star Alliance member airline under any airline code, depending on the booking class. Flights with Star Alliance Connecting Partners are excluded.

Elite Members taking the flights operated by Air China family carriers using their own codes are entitled to bonus mileage; bonus mileage does not count towards your membership status and is credited together with regular mileage.

For reference only,it should based on actual mileage accrual.